A prospective cohort examination of haematological parameters in relation to cancer death and incidence: the Busselton Health Study.

BACKGROUND: Cancer risk is associated with serum iron levels. The aim of this study was to evaluate whether haematological parameters reflect serum iron levels and may also be associated with cancer risk. METHODS: We studied 1564 men and 1769 women who were enrolled in the Busselton Health Study, Western Australia. Haematological parameters evaluated included haemoglobin (Hb), mean cell volume (MCV), mean cell haemoglobin (MCH) and mean cell haemoglobin concentration (MCHC) and red cell distribution width (RCDW). Statistical analyses included t-tests for quantitative variables, chi-square tests for categorical variables and Cox proportional hazards regression modelling for cancer incidence and death. RESULTS: There was marginal evidence of an association between MCV (as a continuous variable) and non-skin cancer incidence in women (HR 1.15, 95% CI 1.013, 1.302; p = 0.030) but the hazard ratio was attenuated to non-significance after adjustment for serum ferritin (SF), iron and transferrin saturation (TS) (HR 1.11, 95% CI 0.972, 1.264; p = 0.126). There was strong evidence of an association between MCHC and prostate cancer incidence in men; the estimated hazard ratio for an increase of one SD (0.5) in MCHC was 1.27 (95% CI 1.064, 1.507; p = 0.008). These results remained significant after further adjustment for SF and iron; the estimated hazard ratio for an increase of one SD (0.5) in MCHC was 1.25 (p = 0.014, 95% CI 1.05 to 1.48). CONCLUSIONS: The MCHC and MCV were associated with cancer incidence in a Western Australian population, although only MCHC remained associated with prostate cancer after adjusting with serum iron and TS (circulating iron) and SF (storage iron). Haematological parameters are thus of limited utility in population profiling for future cancer risk.

Determinants of long-term survival after intensive care.

OBJECTIVE: To identify prognostic determinants of long-term survival for patients treated in intensive care units (ICUs) who survived to hospital discharge. DESIGN: An ICU clinical cohort linked to state-wide hospital records and death registers. SETTING AND PATIENTS: Adult patients admitted to a 22-bed ICU at a major teaching hospital in Perth, Western Australia, between 1987 and 2002 who survived to hospital discharge (n = 19,921) were followed-up until December 31, 2003. MEASUREMENTS: The main outcome measures are crude and adjusted survival. MAIN RESULTS: The risk of death in the first year after hospital discharge was high for patients who survived the ICU compared with the general population (standardized mortality rate [SMR] at 1 yr = 2.90, 95% confidence interval [CI] 2.73-3.08) and remained higher than the general population for every year during 15 yrs of follow up (SMR at 15 yrs = 2.01, 95% CI 1.64-2.46). Factors that were independently associated with survival during the first year were older age (hazard ratio [HR] = 4.09; 95% CI 3.20-5.23), severe comorbidity (HR = 5.23; 95% CI 4.25-6.43), ICU diagnostic group (HR range 2.20 to 8.95), new malignancy (HR = 4.60; 95% CI 3.68-5.76), high acute physiology score on admission (HR = 1.55; 95% CI 1.23-1.96), and peak number of organ failures (HR = 1.51; 95% CI 1.11-2.04). All of these factors were independently associated with subsequent survival for those patients who were alive 1 yr after discharge from the hospital with the addition of male gender (HR = 1.17; 95% CI 1.10-1.25) and prolonged length of stay in ICU (HR = 1.42; 95% CI 1.29-1.55). CONCLUSIONS: Patients who survived an admission to the ICU have worse survival than the general population for at least 15 yrs. The factors that determine long-term survival include age, comorbidity, and primary diagnosis. Severity of illness was also associated with long-term survival and this suggests that an episode of critical illness, or its treatment, may shorten life-expectancy.